A2 Alien Invasive Management Plan 2019 v 1.0.docx

Berg en Dal Estate | Main Road | Hout Bay 7806 | www.bergendalestate.co.za 1

Alien & Invasive Plant Management Plan for Public Areas and Non-Managed Vacant Plots

(updated by Ruth Rupprecht, Landscaping Manager)

The terms “Alien” and “Invasive” as applied to plants are misunderstood by a significant portion of the population. Any plant that is not indigenous to a specific locale can be considered an “Alien” notwithstanding the fact that it may well be indigenous to the country. A plant that at the moment can be considered “non-invasive” may well change its growth pattern and become “invasive” due to climate change or an alteration in available nutrients / water. The main concern with “invasive” plants is not the threat to biodiversity. A recent study in the UK by the Royal Horticultural Society has concluded that “biodiversity” is enhanced when there is a mix of indigenous and alien plants in the region of 80%/20% as it encourages a wider range of insect and bird life. The main problem with invasive plants is that they use significantly more water than non-invasive plants purely down to their density. As South Africa is classed as marginal in the amount of available water the Government has attempted to identify a range of plants that are considered “Alien or Invasive” and have stipulated that these must be controlled so as minimise their effect upon the water table. Unfortunately the legislation, National Environmental Management: Biodiversity Act (NEMBA), does not differentiate between Agricultural, Commercial and Residential Land. The land management of a farm with mainly grazing land is totally different to a small holding producing vegetable and neither is remotely similar to a residential estate such as Berg-en-Dal. Currently the Government is concentrating upon “Alien Removal” on agricultural land as this saves the maximum amount of water, brings land back into profitable use and with the subsidy for doing the actual land clearance, creates a significant number of jobs, especially in the rural areas. The Government, even with the assistance of companies like FNB who invested R9 million in 2011 in the water balance programme, has said that at the current rate of progress they will never manage to remove all the plants on their “Alien/Invasive” list. The Trustees believe that as responsible citizens and homeowners it is incumbent upon all of us to assist in the water management programme. With the technical assistance of Mr Jacques Nel, our previous Garden Manager, we have put together an Alien and Invasive Plant Management programme designed specifically for Berg-en-Dal Estate. We have reviewed the Government “blacklist” of plants that should be controlled, and identified those that are currently resident on the estate. Some of these plants are truly “invasive” and eradication is the only option, others are beautiful as individual signature plants but require new seedlings / suckers to be removed regularly. Some merely need monitoring to ensure their current growth patterns do not change. Below is a list of various plants, along with photographs, giving both the botanical and common name and the management designed by our Garden Manager. These management programmes are to be implemented on the public spaces within the estate and also on any vacant plot which is not being actively managed by its owner. We hope that all the residents of Berg en Dal will also take note of and follow our Alien and Invasive Management Plan. Our Garden Manager is always available to confirm or otherwise what species a plant is and what is the preferred course of management. Please note this is not a definitive list of “Government prescribed Alien / Invasive Plants” but a list of ones which are currently growing on Berg en Dal Estate. This management plan may / will change in the future as plants are either added or removed due to a change in their status.

A2 Alien Invasive Management Plan 2019 v 1.0.docx

Berg en Dal Estate | Main Road | Hout Bay 7806 | www.bergendalestate.co.za 2

Control by Removal

The following plants are considered to be “truly invasive” and the only sensible management plan for these, unless we wish the estate to become over-run, is an aggressive removal programme. Port Jackson Willow (Acacia saligna) This is a very aggressive invader plant that should be removed and destroyed. When removing ensure the roots are dug out or poisoned to prevent re-growth. Do not chip or compost as it will spread the plant by dispersing seeds. Grey Popular / Matchwood Popular (Populus canescens)

The main spreading mechanism for this tree is via suckers which quickly form a dense copse and kill off competing plants. The suckers should not only be dug out but poisoned where possible. Large trees that are aesthetically pleasing in areas of semi-wilderness such as the ravine, should be reviewed and decisions on removal made on individual case by case basis. ALL suckers / seedlings wherever located should be removed

Red Valerian (Centranthus ruber) While this has been considered by some a nice garden plant it is extremely invasive and unless controlled will spread rapidly. Flower colours will range from pale pink, almost white, through to deep red. Given its aggressive colonisation nature and ability to grow almost anywhere it should be removed and destroyed to prevent estate-wide infestations.

A2 Alien Invasive Management Plan 2019 v 1.0.docx

Berg en Dal Estate | Main Road | Hout Bay 7806 | www.bergendalestate.co.za 3

Lantana / Tickberry (Lantana camara) This is a perennial plant so it will re-grow if just cut. The main method of removal is by digging it out; however, care must be taken on large clumps, especially on slopes, that soil erosion does not occur after the stabilizing effect of the plant has been removed. If soil erosion is a worry, a stump herbicide can be applied after cutting down the plant instead of removing the roots. The only effective herbicides are broad-based so should not be used in gardens. Note Nurseries still sell a miniature version which can be grown in private gardens PROVIDING it is carefully controlled and pruned regularly.

Pompom weed (Campuloclinium macrocephalum) A perennial, erect (>1m high) herbaceous plant with attractive fluffy pink/purple blooms in summer, (Dec-March), dies back in winter to a root crown. The stem is covered with rough hairs, leaves are light green. There are no natural predators so it becomes very invasive if left; remove by digging out the root crown. Cutting or herbicides encourage new growth from the crown.

Yellow Oleander (Thevetia peruviana /Cascabela thevetia ) This plant / tree can grow up to 10m high. The best control method is to remove it by digging out the roots while still small. Do not chip or compost as this spreads new growth.

Blackberry/American bramble (Rubus Fruitcosus) This plant needs to be removed by digging it out at the roots as it spreads both by seeds and by suckers. It has a large fibrous root system and it is likely that 2 or 3 attempts will be needed to remove the complete plant.

Wattle (Acacia) There are various species of wattle all of which should be removed by digging out the roots before they grow too large. These by their common name include Cascade Wattle / Red Eye / Silver Wattle / Green Wattle / Pepper Tree Wattle / Fringed Wattle / Screw Pod Wattle / Long Leaved Wattle / Black Wattle / Kangaroo Thorn or Wattle / Pear Acacia / Golden Wattle / Hop Wattle and the Australian Blackwood.

A2 Alien Invasive Management Plan 2019 v 1.0.docx

Berg en Dal Estate | Main Road | Hout Bay 7806 | www.bergendalestate.co.za 4

Crofton Weed (Ageratina adenophora) Mistflower (Ageratina riparia) This plant colonises bare earth however seedlings can tolerate shade and produce large areas of growth. It produces white flowers in the spring and seeds are wind dispersed. Remove by digging out roots after cutting down growth.

Morning Glory (Ipomoea camea) The Morning Glory bush will be removed from Public Land; however, it can be pruned and controlled in well managed gardens. Note it is possible to buy sterile cultivars and hybrids from garden centres which are exempt from the current Aliens and Invasive list.

A2 Alien Invasive Management Plan 2019 v 1.0.docx

Berg en Dal Estate | Main Road | Hout Bay 7806 | www.bergendalestate.co.za 5

Alternate Methods of Control

As Berg en Dal is a managed garden estate with a full-time team of gardeners as well as a Landscaper as Garden Manager it is felt that following plants, although on the Governments Alien List for removal, can be managed successfully, on our estate, without total removal. Sweet Pittosporum (Pittosporum undulatum)

Sweet Pittosporum (Pittosporum undulatum) is a tall evergreen shrub or small tree growing to a height of around 14 m and a spread of 6 m. Its foliage is very dense creating areas of deep shade beneath its canopy. The oval leaves are shiny and dark green, paler beneath and have wavy edges. New growth in winter and spring is a lighter green. The creamy white flowers are found in clusters of 4-5 at the end of stems. They are 2cm long and bell-shaped with a sweet scent. The berries are hard and green, turning yellow then orange. Sweet Pittosporum reproduces by seeds and suckers so it is important to remove all new suckers as they become apparent. This plant does not become

invasive, apart from local suckers, until the annual rainfall exceeds 700mm per annum, significantly more than the 520mm average for Hout Bay. Eugenia Only the Surinam Cherry (Eugenia Uniflora) and the Leafy Spurge (Eugenia Esula), both shown below, are considered to be invasive / alien plants. The Leafy Spurge infests grasslands and as such is not a problem on Berg en Dal. The Surinam Cherry can be controlled by removing all seedlings at an early stage. All other species of Eugenia are not on the Government Blacklist

Surinam Cherry (Eugenia Uniflora) Leafy Spurge (Eugenia esula)

A2 Alien Invasive Management Plan 2019 v 1.0.docx

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Other species of Eugenia are available from Nurseries and make effective windbreaks or can be containerised and shaped as topiary.

Pampas Grass (cortaderia jubata) Pampas grass can grow up to 3 metres tall and can be a striking feature plant providing it is carefully maintained and controlled. For public land the inclusion of mature plants will depend upon the landscape design. To maintain it in a moderate form it should be pruned in late winter early spring. Once it has been cut back it can be shaped by digging through the root ball and removing unwanted growth. Divided sections can be planted elsewhere or destroyed by burning. It is recommended that no more than 1 clump be allowed per plot and where numerous plants have been allowed to develop on vacant plots the majority are removed and destroyed.

Oleander (Nerium Oleander) This plant is useful for hedging or to screen walls etc. On public land it will only be used as a screen to soften harsh features such as a fence, not as a feature. The species Nerium attracts high levels of bees and butterflies. It is not invasive by runners or self-seeding. The municipality uses it as a screen between opposite directions of traffic on dual carriageways. Most plants now available in nurseries are hybrids which are not invasive nor poisonous.

A2 Alien Invasive Management Plan 2019 v 1.0.docx

Berg en Dal Estate | Main Road | Hout Bay 7806 | www.bergendalestate.co.za 7

Cotoneaster (Cotoneaster frachetii) This bush changes its appearance through the seasons. It transforms its small white flowers into red berries, and shows a distinct splattering of red single leaves amongst the green ones. The flowers are attractive to bees and birds and the fruit is attractive to birds in the winter. Spreading tends to be by birds and you will notice a number of off-shoots in the vicinity. Large established trees make a spectacular feature plant which is easily managed by pruning to shape. Seedlings need to be removed as soon as spotted and are easily lifted as their rooting system is quite shallow. It is recommended that the number of these plants is reduced to one or two feature plants per plot or public area. It is requested that homeowners with more than two of these plants reduce the number to two. The Garden Manager can advise on suitable replacement plants.

Eucalyptus There are over 700 species of Eucalyptus of which 6 species are listed but with specific location exemptions. Berg en Dal falls within the scope of the exemptions however we intend to remove all young trees / saplings from public land as a matter of routine. Mature trees will be left unless there is, case by case, convincing argument for removal due to restriction of view or dangerous condition.

Jacaranda(Jacaranda Mimosifolia) While this tree is listed in parts of South Africa, it is not on the prescribed list as far as the Western Cape is concerned, nor is it prescribed within “urban” areas. The estate intends to plant 2 or possibly 3 specimens providing the right site can be identified taking into account the size that the tree will grow to and possible obstruction of views in the long term.

A2 Alien Invasive Management Plan 2019 v 1.0.docx

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Bottlebrush (Callistemon rigidus) There are some 32 types of “Bottlebrush” of which the only one listed is the Stiff Leafed Bottlebrush. Unfortuantely the different plants all look very similar and it is difficult to tell to which genus some species belong. Botanists are currently closely studying these plants to determine how they are best classified. All the species are extremely attractive to birds and insects when flowering. The existing plants on Berg en Dal all appear to have been planted not “self-seeded”. Some species do not release seeds until the parent plant is dying or in danger through fire and others only release the seeds after maturing for 12 months. When seeds are released they only germinate on bare, moist soil and unless correct conditions are achieved within 7 weeks the seeds are no longer viable. Based on the above we have concluded that these are not invasive as far as Berg en Dal is

concerned and that the removal of existing specimens would seriously impact upon the aesthetic nature of the estate. If any homeowner is intending to plant a “Bottlebrush” we would request that they chose an alternative bottlebrush species to Callistemon Ridgidus and the Garden Manager will be happy to advise. Red Flowering Tea Tree (Melaleuca Hypericifolia) Looks similar to the Bottlebrush however the leaves, arranged in pairs, tend to point away from the stem rather than along it. Seed pods remain on the plant for 12 months after flowering before releasing the seeds. Is very tolerant to hard pruning so, if maintained, seed pods are removed at pruning time. Seedlings are not tolerant of wind and require fertiliser in early growth. The adult plants prefer full sun but can utilise most soil conditions. Due to this we do not consider this plant invasive as far as Berg en Dal is concerned but would suggest that any seedlings discovered are removed. As with the bottlebrush this plant is highly attractive to birds when flowering and also as a nesting habitat.

Contact

Should you require more information or have suggestions, please contact our Estate Manager at estatemanager@bergendalestate.co.za or 021 791 0609 to make an appointment with one of our gardening team.